What it means
The measured heater element resistance of the NOx sensor on bank 1 sensor 1 is outside the calibrated range. Used as a sensor-element health check.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
A NOx sensor has a heated sensing element so it can measure nitrogen oxides in the exhaust under suitable conditions, and the control module monitors the heater's electrical resistance at Bank 1 Sensor 1. This code sets when the measured resistance is outside the calibrated range, which can indicate a damaged heater element or a problem in its connector or wiring.
Common causes
Most likely first.
- NOx sensor heater element worn or damaged
- Poor connector contact or corroded terminals
- Open or short in heater wiring
Symptoms
- Check-engine light or NOx warning may illuminate
- Possible emissions warning
How to diagnose it
- Read freeze-frame data and check for related NOx sensor or heater codes to see whether the Bank 1 Sensor 1 heater fault occurs alone.
- With the exhaust cool and the ignition off as directed by the service information, inspect the Bank 1 Sensor 1 connector and heater wiring for corrosion, loose pins, or heat damage.
- Check the heater circuit for an open or short and inspect terminal contact using the wiring diagram and manufacturer's specification.
- Measure the heater element resistance using the manufacturer's procedure and compare it with the specified range.
- If the element and wiring pass, verify the module's heater-circuit control and monitoring before replacing the NOx sensor.
Common fixes
- Clean or repair corroded Bank 1 Sensor 1 heater connector terminals.
- Repair an open, shorted, or heat-damaged heater wire.
- Replace the Bank 1 Sensor 1 NOx sensor if its heater resistance is outside specification.
- Repair the heater control circuit if testing confirms a module-side fault.
Can I keep driving?
The vehicle may remain driveable, but NOx emissions can rise and a NOx or check-engine warning may remain on. Follow any vehicle warning about reduced power, and arrange repair before an emissions inspection.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.